Project Summary/Abstract The objective of this application to the NIH Shared Instrumentation Program is to allow the research community at Stanford University access to a high-density, MR-compatible, functional near-infrared spectroscopy system. The requested instrument (a NIRx 64-source, 64-detector, NIRSport2 with NIRScout2 module) represents a substantial upgrade to the university's neuroimaging resources, and will significantly enhance the institution's cutting-edge, NIH-funded, cognitive and clinical neuroscience research. The requested instrument is unparalleled in its power and sensitivity, and in its flexibility (in terms of the populations for which it is appropriate, and the range of conditions under which it can be used to obtain functional neuroimaging data). Projects for which we will use this new equipment cross the human life span - from critically ill infants, to children and adolescents with neurological, psychiatric, developmental, and behavioral disorders, and aging adults with cognitive impairments (all populations from whom it can be challenging to obtain valid functional MRI data). The research interests of the team of prestigious researchers we have assembled in this proposal is interdisciplinary, integrating fNIRS data with genetic markers, neuropsychological and physiological measures, and other functional neuroimaging and neuromonitoring techniques. The addition of the NIRSport2 will extend NIH-funded projects that improve our understanding of a range of clinical disorders (fragile X syndrome, Klinefelter syndrome, Turner syndrome, autism spectrum disorders, attention deficit hyperactivity disorder, type 1 diabetes), affective disorders (major depressive disorder, anxiety), aging (mild cognitive impairment and Alzheimer's disease), and sleep dysregulation. The research supported by the NIRSport2 system will facilitate the development of novel, and individually-tailored interventions and treatments (i.e. precision medicine), for example, real-time neurofeedback as an early therapeutic intervention for childhood neuropsychiatric disorders and cognitive impairment in aging adults. Further, the modularity of the NIRSport2 will allow us to transform our research with a new emphasis on the neural basis of social interactions and social disorders, since it allows for simultaneous multi-person imaging. The NIRSport2 is also fully ambulatory and thus will enhance our investigations into the effect of aerobic exercise on ADHD and the influence of sleep disordered breathing in autism. These features, combined with the opportunity for whole-head coverage offered by the NIRSport2 allowing the investigation of functional brain circuits, will provide detailed data that elucidate the neural basis of typical and atypical brain function. In summary, access to the requested instrument will significantly enhance the research capabilities of numerous investigators at Stanford, thereby directly contributing to the acquisition of data critical for improving the health and well-being of persons with brain disorders.